8. In this problem, we justify Euler's formula, et = cos(t) + i sin(t). (a) Using the same method as Problem 7, find a second-order linear ODE solved by y(t) = eit. (b) Verify that cos(t) and sin(t) each solve the same ODE you found in (a). Since the general solution can be written c₁ cos(t)+c₂ sin(t), this tells us that eit = C₁ cos(t) + C2 sin(t) for some (possibly complex) numbers C₁, C2. (c) To find c₁ and c2, plug in t = 0 to eit = c₁ cos(t) + c2 sin(t) to get one equation. The other equation comes from differentiating eit =c₁ cos(t) + c₂ sin(t) in t and plugging in t = 0. Solve this system of two equations for c₁ and c₂. When the coefficients of a second-order linear ODE depend on t, we usually cannot find an explicit solution. The following bonus questions discuss two exceptions to this rule.

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question
8. In this problem, we justify Euler's formula, eit
=
cos(t) + i sin(t).
(a) Using the same method as Problem 7, find a second-order linear ODE solved by
y(t) = eit.
(b) Verify that cos(t) and sin(t) each solve the same ODE you found in (a). Since the
general solution can be written c₁ cos(t)+c₂ sin(t), this tells us that eit = C₁ cos(t) +
C2 sin(t) for some (possibly complex) numbers C₁, C2.
(c) To find c₁ and c2, plug in t = 0 to eit = c₁ cos(t) + c2 sin(t) to get one equation. The
other equation comes from differentiating eit = C₁ cos(t) + c₂ sin(t) in t and plugging
in t = 0. Solve this system of two equations for c₁ and c₂.
When the coefficients of a second-order linear ODE depend on t, we usually cannot find an
explicit solution. The following bonus questions discuss two exceptions to this rule.
Transcribed Image Text:8. In this problem, we justify Euler's formula, eit = cos(t) + i sin(t). (a) Using the same method as Problem 7, find a second-order linear ODE solved by y(t) = eit. (b) Verify that cos(t) and sin(t) each solve the same ODE you found in (a). Since the general solution can be written c₁ cos(t)+c₂ sin(t), this tells us that eit = C₁ cos(t) + C2 sin(t) for some (possibly complex) numbers C₁, C2. (c) To find c₁ and c2, plug in t = 0 to eit = c₁ cos(t) + c2 sin(t) to get one equation. The other equation comes from differentiating eit = C₁ cos(t) + c₂ sin(t) in t and plugging in t = 0. Solve this system of two equations for c₁ and c₂. When the coefficients of a second-order linear ODE depend on t, we usually cannot find an explicit solution. The following bonus questions discuss two exceptions to this rule.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 2 images

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,